The present invention relates generally to a non-invasive apparatus and method for detecting blood flow in the vascular system for the purpose of detecting vascular pathology.
Cerebrovascular disease is the most common neurological disorder. Cerebrovascular disease is the major cause of hospitalization. For example, there are 500,000 new patients with strokes each year in the United States, and each year, strokes kill 175,000 people and disable 200,000 people in the United States.
Pathological changes in brain vessels begin years before the dramatic stroke kills or paralyzes a person. When a physician sends a patent for angiography, an MRI or a CAT scan, it is often too late. In this regard, it is desirable to provide a quick diagnosis in an emergency room and in private practice to detect cerebrovascular problems at an early stage.
Various auscultation devices are known which are capable of listening to sounds arising within organs as an aid to diagnosis and treatment. Such devices aid a doctor in providing a correct diagnosis by providing more detailed and specific sound information than is possible using an ordinary stethoscope. Further, such devices often permit the recording, processing and displaying of various characteristics of the captured sounds.
However, none of these devices are designed to detect cerebrovascular pathology.
For example, U.S. Pat. No. 4,008,711 to Olinger et al, discusses the detection of aneurysms where the frequency range is 200 Hz to 800 Hz, using computerized models on a Hewlett Packard fourier analyzer model 5451. It is known that a frequency range from human organs is a constant physiological value between 10 Hz and 300 Hz. In like manner, U.S. Pat. No. 4,928,705 to Sekhar et al discloses an acoustic aneurysm detector which uses hydrophonic sensors implanted in a helmet and which make contact with the skull. However, the preferred frequency range is 100 Hz to 1,000 Hz and Sekhar et al uses an EKG and computer.